Prefetch Frames not working?
The Cache is designed to be as unobtrusive as possible. That's the reason, you don't see the orange cache bars. It should be working, however. If you want to see the cache bars, you should do the following:
(1) Enable Developers Extra in the Edit &gt; Preferences &gt; Interface panel.
(2) Enable the cache Bars in the View &gt; Show Cache menu of the Sequencer.